The present invention is in a textile flame barrier as a part of a planar multi-layer structure.
Known flame barriers are difficultly flammable fabrics which have numerous uses including: flame-retarding clothing; interior equipment of the passenger areas in air, land and sea crafts; vehicle equipment such as tarpaulins or interior linings of engine compartments; upholstery material; textile interior linings of rooms; and in cushions and mattresses.
The term flame barrier relates to a barrier that prevents a flame from penetrating a visible material into the interior of one of the above objects. "Melliand Textilberichte" (Melliand textile reports) gives a detailed account of these properties (6/1987, 396-401).
The use a light-weight nonwoven fabric made of a difficultly flammable material has been proposed. (Melliand Textilberichte 1987, 396-401). The publication lists numerous organic and inorganic, difficultly flammable fiber materials and sets forth the Limiting-Oxygen-Index thereof (hereinafter - LOI-value). This index reflects the flammability of plastics according to ISO-standard 4589 "Plastics - classification of flammability based on the Oxygen-Index". This standard may also be applied to textiles provided these are made of an organic fiber material. In our atmosphere, effective flame-retarding properties can be expected at LOI-values above approximately 27.
U.S. Pat. No. 4,748,065 discloses a nonwoven fabric for flame protection purposes impregnated with carbon particles which absorb chemical fumes. That fabric is used for fireproof clothing. 90% of the nonwoven material is made of aramide staple fibers. The nonwoven material has a weight per unit area of 35 to 70 g/m.sup.2. The fibers are bonded by a double water-jet-treatment, applying a pressure of approximately 1400 kPa once and then jet pressures between 10,000 and 11,000 kPa. The absorbing carbon particles for impregnation, present in an amount of 10 to 50 wt.-%, serve exclusively for the sorption of harmful gases. The carbon particles do not affect the flammability.
This prior art flame-retarding nonwoven fabric consists essentially of still meltable fibers and, hence, is destroyed when directly exposed to flames. That fabric does not pass the flame test according to ISO 8191-1 and -2 and cannot be considered a flame barrier.